阅读说明：本技术 一种逆变器最优输出控制方法和装置 (inverter optimal output control method and device ) 是由 鲁海波 黄敏 方刚 卢进军 于 2019-08-22 设计创作，主要内容包括：本发明涉及一种逆变器最优输出控制方法,包括以下步骤：步骤1：计算逆变器当前的逆变功率；步骤2：判断逆变器当前的逆变功率所属的功率等级,获得该对应的输出控制环参数调节限值和调节步长；步骤3：计算调节前逆变器输出信号的总谐波电流值；步骤4：按照调节步长和调节方向对输出控制环的参数进行调节；步骤5：计算调节后逆变器输出信号的总谐波电流值；步骤6：判断调节后相比调节前逆变器输出信号的总谐波电流值是否变大,若变大则改变调节方向后返回步骤3,否则维持当前调节方向并返回步骤3。本发明能够保证逆变器适应不同的现场电网工况,使逆变器的输出性能达到最优。(The invention relates to an optimal output control method of an inverter, which comprises the following steps: step 1: calculating the current inversion power of the inverter; step 2: judging the power grade of the current inversion power of the inverter to obtain the corresponding output control loop parameter regulation limit value and regulation step length; and step 3: calculating the total harmonic current value of the output signal of the inverter before regulation; and 4, step 4: adjusting parameters of the output control loop according to the adjustment step length and the adjustment direction; and 5: calculating the total harmonic current value of the regulated output signal of the inverter; step 6: and (3) judging whether the total harmonic current value of the output signal of the inverter after adjustment is larger than that before adjustment, if so, changing the adjustment direction and returning to the step (3), otherwise, maintaining the current adjustment direction and returning to the step (3). The invention can ensure that the inverter is suitable for different field power grid working conditions, so that the output performance of the inverter is optimal.)

1. An inverter optimal output control method for controlling an output of an inverter by adjusting a parameter of an output control loop, characterized in that: the optimal output control method of the inverter comprises the following steps:

step 1: calculating the current inversion power of the inverter;

Step 2: judging the power grade of the current inversion power of the inverter, obtaining the output control loop parameter regulation limit value and regulation step length corresponding to the power grade, and setting the regulation direction;

and step 3: calculating the output signal of said inverter before regulationna sub-total harmonic current value;

And 4, step 4: adjusting the parameters of the output control loop according to the adjustment step length and the adjustment direction within the range limited by the parameter adjustment limit value of the output control loop;

and 5: calculating the regulated output signal of the inverternA sub-total harmonic current value;

step 6: determining the output signal of the inverter after regulationncomparing the value of the sub-total harmonic current with the output signal of the inverter before regulationnand (4) whether the value of the sub-total harmonic current is increased or not, if so, changing the adjusting direction and then returning to the step (3), otherwise, maintaining the current adjusting direction and returning to the step (3).

2. The inverter optimum output control method according to claim 1, characterized in that: in the step 1, the current inversion power of the inverter is calculated by adopting an integration method according to the inversion sampling current and the inversion sampling voltage of the inverter.

3. The inverter optimum output control method according to claim 1, characterized in that: in step 2, the adjustment direction is initially set to increase.

4. the optimal inverter output control method according to claim 1, wherein in the step 3, the 2-7 total harmonic current values of the output signals of the inverter before the adjustment are calculated by using a correlation method according to the inversion sampling current of the inverter, and in the step 5, the 2-7 total harmonic current values of the output signals of the inverter after the adjustment are calculated by using a correlation method according to the inversion sampling current of the inverter.

5. The inverter optimum output control method according to claim 1, characterized in that: the method comprises the steps of dividing the inverter power of the inverter into five power levels in advance, and presetting an output control loop parameter regulation limit value and a regulation step length corresponding to each power level.

6. An inverter optimum output control apparatus for controlling an inverter, characterized in that: the inverter optimal output control apparatus includes an inverter controller that controls the inverter by using the inverter optimal output control method according to any one of claims 1 to 5.

7. The inverter optimum output control device according to claim 6, characterized in that: the inverter controller outputs a PWM signal for controlling the inverter through the output control loop.

Technical Field

The invention belongs to the field of photovoltaic power generation, and particularly relates to a method and a device for controlling the output of an inverter in a photovoltaic system.

Background

The inverter operates under the control of the inverter controller. Existing inverter controllers typically use a conventional PI control loop to implement the control function. Because the parameters in the PI control loop are fixed, the PI control loop is limited by site adverse working conditions such as high impedance of a power grid, quality of the power grid and the like, and the quality of electric energy output by inversion cannot reach the optimum.

Disclosure of Invention

The invention aims to provide an optimal output control method of an inverter, which can ensure that the inverter is suitable for different field power grid working conditions and the output performance of the inverter is optimal.

In order to achieve the purpose, the invention adopts the technical scheme that:

An inverter optimal output control method for controlling an output of an inverter by adjusting a parameter of an output control loop, the inverter optimal output control method comprising the steps of:

Step 1: calculating the current inversion power of the inverter;

Step 2: judging the power grade of the current inversion power of the inverter, obtaining the output control loop parameter regulation limit value and regulation step length corresponding to the power grade, and setting the regulation direction;

And step 3: calculating the n-th total harmonic current value of the output signal of the inverter before regulation;

And 4, step 4: adjusting the parameters of the output control loop according to the adjustment step length and the adjustment direction within the range limited by the parameter adjustment limit value of the output control loop;

and 5: calculating the n-th total harmonic current value of the regulated output signal of the inverter;

Step 6: and judging whether the n-th total harmonic current value of the output signal of the inverter after adjustment is larger than the n-th total harmonic current value of the output signal of the inverter before adjustment, if so, changing the adjustment direction and returning to the step 3, otherwise, maintaining the current adjustment direction and returning to the step 3.

In the step 1, the current inversion power of the inverter is calculated by adopting an integration method according to the inversion sampling current and the inversion sampling voltage of the inverter.

in step 2, the adjustment direction is initially set to increase.

In the step 3, calculating a 2-7-order total harmonic current value of an output signal of the inverter before regulation by using a correlation method according to the inversion sampling current of the inverter; and in the step 5, calculating the 2-7 times total harmonic current value of the regulated output signal of the inverter by using a correlation method according to the inversion sampling current of the inverter.

the method comprises the steps of dividing the inverter power of the inverter into five power levels in advance, and presetting an output control loop parameter regulation limit value and a regulation step length corresponding to each power level.

The invention also provides an inverter optimal output control device which can ensure that the inverter is suitable for different field power grid working conditions and the output performance of the inverter is optimal. The inverter controller outputs a PWM signal for controlling the inverter through the output control loop.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: according to the invention, through dynamic adjustment of the parameters of the output control loop, the inverter can be ensured to adapt to different field power grid working conditions, so that the output performance of the inverter is optimal.

drawings

fig. 1 is a flow chart diagram of an inverter optimal output control method of the present invention.

Fig. 2 is a flowchart of determining a power level to which the inverter power of the inverter belongs in the inverter optimal output control method of the present invention.

Fig. 3 is a flowchart of an inverter optimum output control method of the present invention.

Detailed Description

The invention will be further described with reference to examples of embodiments shown in the drawings to which the invention is attached.